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comparison Meerwald-dir/cmp_zhu_sig.c @ 24:9f20bce6184e v0.7

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move directories, support netpbm 11
author Peter Meerwald-Stadler <pmeerw@pmeerw.net>
date Fri, 20 Dec 2024 13:08:59 +0100
parents Meerwald/cmp_zhu_sig.c@f83ef905a63d
children
comparison
equal deleted inserted replaced
23:71dd4b96221b 24:9f20bce6184e
1 #include "wm.h"
2
3 char *progname;
4
5 void usage(void) {
6 fprintf(stderr, "usage: %s [-h] [-C] [-o file] [-v n] -s file file\n\n", progname);
7 fprintf(stderr, "\t-C\t\toutput correlation only\n");
8 fprintf(stderr, "\t-h\t\tprint usage\n");
9 fprintf(stderr, "\t-o file\t\toutput file\n");
10 fprintf(stderr, "\t-v n\t\tverbosity level\n");
11 fprintf(stderr, "\t-s file\t\toriginal signature file\n");
12 exit(0);
13 }
14
15 int main(int argc, char *argv[]) {
16
17 FILE *in = stdin;
18 FILE *out = stdout;
19 FILE *sig = NULL;
20
21 char signature_name[MAXPATHLEN];
22 char output_name[MAXPATHLEN] = "(stdout)";
23 char input_name[MAXPATHLEN] = "(stdin)";
24
25 int c, i, j, n;
26 int in_level;
27 double *cumul_watermark, *orig_watermark;
28 int *cumul_watermark_count;
29 int sig_n, in_n;
30 double sig_a;
31 int sig_l;
32 int sig_e, sig_f;
33 char line[32];
34 double correlation, maxcorrelation;
35 double s1, s2, s3;
36
37 int verbose = 0;
38 int correlation_only = 0;
39
40 progname = argv[0];
41
42 while ((c = getopt(argc, argv, "h?Co:s:v:")) != EOF) {
43 switch (c) {
44 case 'h':
45 case '?':
46 usage();
47 break;
48 case 'C':
49 correlation_only = 1;
50 break;
51 case 'o':
52 if ((out = fopen(optarg, "w")) == NULL) {
53 fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
54 exit(1);
55 }
56 strcpy(output_name, optarg);
57 break;
58 case 's':
59 if ((sig = fopen(optarg, "r")) == NULL) {
60 fprintf(stderr, "%s: unable to open signature file %s\n", progname, optarg);
61 exit(1);
62 }
63 strcpy(signature_name, optarg);
64 break;
65 case 'v':
66 verbose = atoi(optarg);
67 if (verbose < 0) {
68 fprintf(stderr, "%s: verbosity level %d out of range\n", progname, verbose);
69 exit(1);
70 }
71 break;
72 }
73 }
74
75 argc -= optind;
76 argv += optind;
77
78 if (argc > 1) {
79 usage();
80 exit(1);
81 }
82
83 if (argc == 1 && *argv[0] != '-') {
84 if ((in = fopen(argv[0], "r")) == NULL) {
85 fprintf(stderr, "%s: unable to open input file %s\n", progname, argv[0]);
86 exit(1);
87 }
88 else
89 strcpy(input_name, argv[0]);
90 }
91
92 if (!sig) {
93 fprintf(stderr, "%s: original signature file not specified, use -s file option\n", progname);
94 exit(1);
95 }
96
97 fgets(line, sizeof(line), sig);
98 if (strspn(line, "ZHSG") < 4) {
99 fprintf(stderr, "%s: original signature file %s invalid\n", progname, signature_name);
100 exit(1);
101 }
102
103 fgets(line, sizeof(line), in);
104 if (strspn(line, "ZHWM") < 4) {
105 fprintf(stderr, "%s: watermark file %s invalid\n", progname, input_name);
106 exit(1);
107 }
108
109 fscanf(sig, "%d\n", &sig_n);
110 fscanf(in, "%d\n", &in_n);
111 if (sig_n != in_n) {
112 fprintf(stderr, "%s: watermark length mismatch (original %d, input %d)\n", progname, sig_n, in_n);
113 exit(1);
114 }
115 if (sig_n <= 0 || sig_n > 32000) {
116 fprintf(stderr, "%s: invalid original watermark length %d\n", progname, sig_n);
117 exit(1);
118 }
119 if (in_n != sig_n) {
120 fprintf(stderr, "%s: invalid watermark length %d, does not match signature length\n", progname, in_n);
121 exit(1);
122 }
123
124 fscanf(sig, "%lf\n", &sig_a);
125 fscanf(sig, "%d\n", &sig_l);
126 fscanf(sig, "%d\n", &sig_e);
127 fscanf(sig, "%d\n", &sig_f);
128 fscanf(sig, "%*[^\n\r]\n");
129
130 orig_watermark = malloc(sig_n * sizeof(double));
131 for (i = 0; i < sig_n; i++)
132 fscanf(sig, "%lf\n", &orig_watermark[i]);
133 fclose(sig);
134
135 fscanf(in, "%d\n", &in_level);
136
137 cumul_watermark = malloc(in_n * sizeof(double));
138 cumul_watermark_count = malloc(in_n * sizeof(int));
139
140 for (i = 0; i < in_n; i++) {
141 cumul_watermark_count[i] = 0;
142 cumul_watermark[i] = 0.0;
143 }
144
145 /*
146 * normalized correlation
147 * Craver, S., "Can Invisible Watermarks Resolve Rightful Ownership?", IBM Research Report, 1996, p. 5
148 */
149 maxcorrelation = -10000.0;
150 for (i = 0; i < in_level; i++) {
151 fscanf(in, "%d\n", &n);
152
153 s1 = s2 = s3 = 0.0;
154 for (j = 0; j < n; j++) {
155 double in_x, sig_x;
156
157 sig_x = orig_watermark[j];
158 fscanf(in, "%lf\n", &in_x);
159
160 s1 += sig_x * in_x;
161 s2 += in_x * in_x;
162 s3 += sig_x * sig_x;
163
164 if (verbose > 2)
165 fprintf(stderr, "%s: level %d; orig %f input %f\n", progname, i, sig_x, in_x);
166
167 cumul_watermark[j % in_n] += in_x;
168 cumul_watermark_count[j % in_n]++;
169 }
170
171 correlation = s1 / sqrt(s2 * s3);
172 if (correlation > maxcorrelation)
173 maxcorrelation = correlation;
174
175 if (!correlation_only)
176 fprintf(out, "%s: correlation level %d: %f\n", progname, i, correlation);
177 }
178
179 s1 = s2 = s3 = 0.0;
180 for (i = 0; i < in_n; i++) {
181 double in_x, sig_x;
182
183 in_x = cumul_watermark[i] / (double) cumul_watermark_count[i];
184 sig_x = orig_watermark[i];
185
186 s1 += sig_x * in_x;
187 s2 += in_x * in_x;
188 s3 += sig_x * sig_x;
189 }
190
191 correlation = s1 / sqrt(s2 * s3);
192 if (!correlation_only)
193 fprintf(out, "%s: cumultative correlation: %f\n", progname, correlation);
194
195 if (correlation > maxcorrelation)
196 maxcorrelation = correlation;
197
198 if (!correlation_only)
199 fprintf(out, "%s: max. correlation: %f\n", progname, maxcorrelation);
200 else
201 fprintf(out, "%f\n", maxcorrelation);
202
203 fclose(out);
204 fclose(in);
205
206 free(orig_watermark);
207 free(cumul_watermark);
208 free(cumul_watermark_count);
209
210 exit(0);
211 }

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